This section provides background information related to the present disclosure which is not necessarily prior art.
Differential assemblies that employ a helical gearset, sometimes referred to as “parallel-axis differential assemblies”, typically employ an extremely heavy-duty differential case for housing into which the gearset is received. One such parallel-axis differential assembly is disclosed in U.S. Pat. No. 5,842,946. The housing of a parallel-axis differential assembly typically defines a central bore that is intersected by sets of parallel bores. A pair of side gears are typically received in the central bore, while the sets of parallel bores house a pair of pinions. As is well known in the art, rotational energy input to the differential case is transmitted through the pinions into the side gears. The surfaces of the pinion bores are configured to provide desired frictional characteristics or tribological properties that permit the differential assembly to differentiate torque in a desired manner.
Since all of the rotary power that is transmitted to the gearset is transmitted through the differential case, and since the differential case is typically cast, the structure of the differential case tends to be extremely heavy, which drives up the total mass and cost of the differential assembly. Moreover, it can be difficult and/or costly in some situations to alter the tribological properties of the differential case given for example limitations on the material of the differential case and/or the size or mass of the differential case. Accordingly, there remains a need in the art for a parallel-axis differential having improved performance, reduced cost, and/or reduced mass.